JP2006071959A - Acoustic material and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acoustic material which is excellent in lightweight and high in rigidity and is suitable as a hood silencer and dash silence in an engine room of an automobile. <P>SOLUTION: The acoustic material is composed of a polyurethane foam 11, a surface material 21 laminated and adhered to one surface of the polyurethane foam 11, and a thermosetting resin-containing hardened felt 31 laminated and adhered to the surface of the polyurethane foam 11 on the side opposite from the surface material 21. The bending rigidity of the acoustic material is 6 to 10 N/25 mm. The surface material may be laminated and adhered to the surface of the thermosetting resin-containing hardened felt 31 on the side opposite from the polyurethane foam 11. The surface material 21 is suitably a non-woven fabric. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sound absorbing material and a method for manufacturing the same.

  Conventionally, sound absorbing materials have been used in various fields. For example, in the field of automobiles, there are sound absorbing materials such as a hood silencer disposed on the back side of the hood in an engine room and a dash silencer disposed on the boundary with the vehicle interior.

  Many of the sound absorbing materials have a structure in which a surface material and a base material are laminated and bonded. The surface material of the sound absorbing material is generally a non-woven fabric coated with a hot melt resin or a thermosetting resin, and the substrate is generally felt or glass wool containing a thermosetting resin. .

  A conventional method for producing a sound absorbing material is performed by laminating a nonwoven fabric coated with a hot melt resin or a thermosetting resin, and felt or glass wool containing the thermosetting resin, followed by hot pressing.

However, the conventional sound absorbing material and the manufacturing method thereof have a problem that the sound absorbing material becomes heavy because the base material is made only of felt or glass wool containing a thermosetting resin. Also, there is a method of using polyurethane foam as a base material in order to reduce the weight of the sound absorbing material, but in that case, in terms of rigidity compared to a sound absorbing material using a base material made of felt or glass wool containing a thermosetting resin. Inferior, depending on where the sound absorbing material is used, the sound absorbing material may not be properly held.
JP 2004-106477 A JP 2004-27383 A

  This invention is made | formed in view of the said point, Comprising: It is excellent in lightweight property, and provides a highly rigid sound-absorbing material and its manufacturing method.

  The invention of claim 1 is a polyurethane foam, a surface material laminated and adhered to one side of the polyurethane foam, and a thermosetting resin-containing cured felt laminated and adhered to the surface of the polyurethane foam opposite to the surface material. It is related with the sound-absorbing material characterized by comprising.

  According to a second aspect of the present invention, in the first aspect, the bending rigidity of the sound absorbing material is 6 to 10 N / 25 mm.

  According to a third aspect of the present invention, in the first or second aspect, the surface material is laminated and bonded to one surface of the polyurethane foam and the surface of the thermosetting resin-containing cured felt opposite to the polyurethane foam. It is characterized by.

  A fourth aspect of the invention is characterized in that, in any one of the first to third aspects, the surface material is made of a nonwoven fabric.

  The invention of claim 5 includes a step of impregnating the surface material with a catalyst mixed emulsion obtained by mixing a liquid binder catalyst with an aqueous emulsion of a water repellent agent to obtain a catalyst mixed emulsion-impregnated surface material; A step of applying a catalyst-free liquid binder to obtain a catalyst-free liquid binder-attached polyurethane foam, and a thermosetting resin containing a thermosetting resin and at least a part of the thermosetting resin being in an uncured state Uncured felt is laminated on one side of the catalyst-free liquid binder-attached polyurethane foam, and the catalyst-mixed emulsion on the surface opposite to the thermosetting resin-containing uncured felt in the catalyst-free liquid binder-attached polyurethane foam. A step of laminating impregnated surface material, the thermosetting resin-containing uncured felt, and the catalyst The laminated body of the polyurethane foam containing the liquid binder and the catalyst mixed emulsion impregnated surface material is hot-pressed to cure the liquid binder and bond the laminated body together, and the uncured felt containing the thermosetting resin And a heat pressing step of curing the thermosetting resin to form, and a method for producing a sound-absorbing material.

  The invention of claim 6 is the thermosetting resin composition according to claim 5, wherein the thermosetting resin-containing uncured felt, the catalyst-free liquid binder-attached polyurethane foam, and the catalyst-mixed emulsion-impregnated surface material are laminated. The catalyst-mixed emulsion-impregnated surface material is laminated on the surface of the resin-containing uncured felt opposite to the catalyst-free liquid binder-attached polyurethane foam, followed by hot pressing.

  According to the invention of claim 1, the sound absorbing material is a polyurethane foam, a surface material laminated and adhered to one surface of the polyurethane foam, and a thermosetting material laminated and adhered to the surface of the polyurethane foam opposite to the surface material. Because the polyurethane foam and the thermosetting resin-containing cured felt constitute the base material of the sound-absorbing material, the base material consists only of the thermosetting resin-containing cured felt, or thermosetting The sound-absorbing material becomes lighter compared to the case where it is made of only the cured resin-containing cured glass wool. Furthermore, the sound-absorbing material of the present invention has higher rigidity due to the presence of the thermosetting resin-containing cured felt, as compared with the case where the base material of the sound-absorbing material is composed of only polyurethane foam.

  According to invention of Claim 2, since the bending rigidity of a sound-absorbing material is 6-10N / 25mm, the shape retainability of a sound-absorbing material becomes favorable.

  According to the invention of claim 3, since the surface material is laminated and bonded to the surface of the thermosetting resin-containing cured felt, the thermosetting resin-containing cured felt can be protected.

  According to the invention of claim 4, since the surface material is made of a nonwoven fabric, it becomes easy for sound to enter the polyurethane foam through the nonwoven fabric, and sound absorption can be favorably performed by the polyurethane foam.

  According to inventions of claims 5 and 6, the catalyst-free liquid binder-adhered polyurethane foam is laminated with the thermosetting resin-containing uncured felt and the catalyst-mixed emulsion-impregnated surface material and is heated until it is hot pressed. Does not exert an adhesive action and is easy to handle. And since both adhesion | attachment and shaping are performed by a hot press, the sound-absorbing material which is lightweight and has the rigidity which can hold | maintain a shape can be manufactured easily.

  FIG. 1 is a cross-sectional view of a sound absorbing material according to the first embodiment of the present invention, FIG. 2 is a schematic view showing impregnation of a surface mixture with a catalyst mixed emulsion during production of the sound absorbing material according to the first embodiment, and FIG. FIG. 4 is a schematic view showing a case where a catalyst-free liquid binder is applied to both surfaces of a polyurethane foam during the production of the sound absorbing material according to the first embodiment. FIG. FIG. 5 is a cross-sectional view of a sound absorbing material according to the second embodiment of the present invention, and FIG. 6 shows an example of lamination and heat pressing during the production of the sound absorbing material according to the second embodiment. It is sectional drawing.

  A sound absorbing material 10 according to the first embodiment shown in FIG. 1 includes a polyurethane foam 11, a surface material 21 laminated and bonded to one surface of the polyurethane foam 11, and the surface material 21 opposite to the surface material 21 of the polyurethane foam 11. It consists of a thermosetting resin-containing cured felt 31 laminated and bonded to the surface, and is suitable for use in an automobile engine room. The polyurethane foam 11 and the thermosetting resin-containing curing felt 31 correspond to the base material of the sound absorbing material 10.

The polyurethane foam 11 is preferably a slab polyurethane foam cut into a sheet. The soft slab polyurethane foam is usually one in which a soft polyurethane foam stock solution is flowed on a continuous conveyor, the foam is continuously foamed into a square or kamaboko shape, and then cut into a predetermined length. Since it has high air permeability and is inexpensive, it is suitable as a constituent member of the sound absorbing material in the present invention. The soft slab polyurethane foam is particularly preferably one having a density of 5 to 20 kg / m ^{3 in} order to obtain better air permeability and light weight. Moreover, although the polyurethane foam 11 in the said sound-absorbing material 10 is set as appropriate thickness, 10-50 mm is mentioned as an example.

The surface material 21 is made of an appropriate material, but is preferably a non-woven fabric because of the ease of sound passage. As the nonwoven fabric, an appropriate one can be used, but when the sound absorbing material 10 is for an engine room, a polyester fiber nonwoven fabric having excellent heat resistance is preferred so that it can withstand the high temperature in the engine room. Particularly preferred is a polyester fiber spunbonded non-woven fabric that is needle-punched with a basis weight of 30 to 100 g / m ² . Further, it is preferable that a water repellent is dispersed in the surface material 21. In particular, in a sound-absorbing material used in a place where condensation is likely to occur or where moisture is likely to adhere, such as an engine room of an automobile having a large temperature difference between running and stopped, a water repellent is applied to the surface material 21. It is preferable to disperse water to impart water repellency. As the water repellent dispersed in the surface material 21, an appropriate one can be used. However, when the sound absorbing material 10 is used for an engine room of an automobile, one having good heat resistance is preferable. Is preferred. The water repellent agent is made into an aqueous emulsion, impregnated in the surface material 21, and the water repellent material is dispersed and fixed to the surface material 21 by evaporating the water content of the emulsion by hot pressing during the production of the sound absorbing material.

  The thermosetting resin-containing cured felt 31 is obtained by curing a thermosetting resin of a thermosetting resin-containing uncured felt. Moreover, in this invention, the said thermosetting resin containing uncured felt means what contains a thermosetting resin in a fiber component, and at least one part of this containing thermosetting resin is in an uncured state. Examples of the fiber component include wool, cotton, polyester fiber, nylon fiber, rayon, acrylic fiber, polyethylene fiber, polypropylene fiber, carbon fiber, glass wool, and other organic or inorganic natural or synthetic fibers or metal fibers. Can be mentioned. Thermosetting resins include phenol (or phenol derivatives such as phenol or cresol, xylenol, resorcin, or bisphenol A) and formaldehyde (formaldehyde or formaldehyde equivalents such as paraformaldehyde, formalin, or trioxane). Or a novolac phenol resin obtained by reacting with an acid catalyst (oxalic acid, sulfuric acid, hydrochloric acid, paratoluenesulfonic acid, etc.), or a mixture of a novolac phenol resin and a resol phenol resin, Alternatively, polyurethane resin, urea resin, melamine resin, acrylic resin, alkyd resin, and the like can be given. Generally, a phenol resin is used from the viewpoint of good curability and the like. The said thermosetting resin is 10-60 weight part with respect to 100 weight part of fiber components, Preferably it is 20-50 weight part. In addition, a well-known thing can be used for the said thermosetting resin containing uncured felt.

  The interface K1 between the polyurethane foam 11 and the surface material 21 and the interface K2 between the polyurethane foam 11 and the thermosetting resin-containing curing felt 31 are bonded together by curing a liquid binder. As the liquid binder, an isocyanate adhesive is preferable. Furthermore, as the isocyanate adhesive, methylene diphenyl diisocyanate (MDI) is preferable in terms of good heat resistance and ease of handling. The isocyanate adhesive is cured by moisture in the presence of a catalyst and exhibits adhesiveness.

  Next, an embodiment of the method for manufacturing the sound absorbing material 10 will be described. The method for producing the sound absorbing material 10 includes a step of obtaining a catalyst-impregnated surface material of a liquid binder, a step of obtaining a catalyst-free liquid binder-attached polyurethane foam, a laminating step, and a hot pressing step.

  In the step of obtaining the catalyst-impregnated surface material of the liquid binder, first, a step of preparing a catalyst mixed emulsion is performed. In the catalyst mixed emulsion preparation step, a liquid binder catalyst is mixed with the water-repellent aqueous emulsion. When the liquid binder is an isocyanate adhesive, an isocyanate adhesive catalyst is used as the liquid binder catalyst. An amine catalyst is suitable as the catalyst for the isocyanate adhesive. Next, as shown in FIG. 2, the catalyst mixed emulsion E obtained in the catalyst mixed emulsion preparation step is applied to and impregnated on the surface material (for example, non-woven fabric) 21, and the catalyst-impregnated surface material 21a of a liquid binder is applied. obtain. Application of the catalyst mixed emulsion can be performed by an appropriate method, but spray application is preferable because it is easy to work. The application amount of the catalyst mixed emulsion is an appropriate amount, and the optimum amount varies depending on the material, thickness, basis weight, etc. of the surface material 21 (for example, non-woven fabric).

  In the step of obtaining the catalyst-free liquid binder-attached polyurethane foam, as shown in FIG. 3, a catalyst-free liquid binder (for example, catalyst-free isocyanate adhesive) B is applied to both surfaces of the polyurethane foam 11. The catalyst-free liquid binder-attached polyurethane foam 11a is obtained. The catalyst-free liquid binder can be applied by an appropriate method, but spray coating is preferable because it is easy to work. Further, the catalyst-free liquid binder is an appropriate coating amount and varies depending on the density and thickness of the polyurethane foam 11, but the catalyst-free liquid binder is formed on the surface of the surface material made of a nonwoven fabric during subsequent hot pressing. An amount that does not bleed out and does not cause insufficient adhesion to the surface material is preferable.

  In the lamination step, as shown in FIG. 4, the thermosetting resin-containing uncured felt 31a is laminated on one surface of the catalyst-free liquid binder-attached polyurethane foam 11a, and the catalyst-free liquid binder-attached polyurethane foam 11a The catalyst-mixed emulsion-impregnated surface material 21a is laminated on the surface opposite to the thermosetting resin-containing uncured felt 31a to form an unadhered three-layer laminate. At that time, it is preferable that the catalyst-mixed emulsion-coated surface of the catalyst-mixed emulsion-impregnated surface material 21a be opposed to the surface of the catalyst-free liquid binder-attached polyurethane foam 11a.

  In the hot pressing step, an unadhered laminate of the thermosetting resin-containing uncured felt 31a, the catalyst-free liquid binder-attached polyurethane foam 11a, and the catalyst-mixed emulsion-impregnated surface material 21a is formed into a hot press die 41, Hot press with 42. The hot press temperature is set to a temperature at which the liquid binder is reactively cured and the thermosetting resin is cured. When the liquid binder is an isocyanate adhesive, 160 to 220 ° C. is preferable. In the case of the hot pressing, when the liquid binder of the catalyst-free liquid binder-attached polyurethane foam 11a is in contact with the catalyst of the catalyst-mixed emulsion-impregnated surface material 21a and the liquid binder is an isocyanate adhesive, the isocyanate adhesive Reacts with the moisture of the catalyst-mixed emulsion-impregnated surface material 21a to be cured by reaction, and the laminate is bonded together. At the same time, the thermosetting resin of the thermosetting resin-containing uncured felt 31a is cured by the heat during the hot pressing, and the laminate is shaped to obtain the sound absorbing material 10 shown in FIG. . The sound absorbing material 10 thus obtained has water repellency due to the water repellent contained in the surface material 11.

  Further, when the surface material 21 is a non-woven fabric during the hot pressing, the water content of the aqueous emulsion in the catalyst-mixed emulsion-impregnated surface material 21a evaporates all at once. (Nonwoven fabric) 21 A communication hole communicating from the inside to the surface is formed, and the sound absorbing property of the sound absorbing material 10 is improved by the communication hole of the surface material 21. When the temperature of the hot press is lower than 160 ° C., it takes time to cure the isocyanate adhesive and the thermosetting resin, and it is difficult to evaporate the water at once, and the evaporation path trace is formed. The air passage is interrupted or thinned in the middle, making it difficult to obtain good air permeability, and the sound absorbing property of the sound absorbing material 10 is lowered. On the other hand, when the temperature is higher than 220 ° C., the nonwoven fabric or the polyurethane foam may cause problems such as deterioration due to heat. In addition, the compression amount of the laminated body at the time of the hot pressing is appropriately set depending on the thickness of the target sound absorbing material 10 or the like. In FIG. 4, the maximum compression amount at the time of the hot press is adjusted by the spacers 43, 43 arranged between the hot press dies 41,. The hot press dies 41, 42 are provided with heating means such as an electric heater so that the hot press dies 41, 42 can be heated.

  FIG. 5 is a cross-sectional view of the sound absorbing material 10A according to the second embodiment. In the sound absorbing material 10A of the second embodiment, the surface material 22 is laminated and adhered to one surface of the polyurethane foam 11 and the surface opposite to the polyurethane foam 11 in the thermosetting resin-containing cured felt 31. Unlike the sound absorbing material 10 of one embodiment, the other configurations are the same as those of the sound absorbing material 10 of the first embodiment. Regarding the sound absorbing material 10A of the second embodiment, the same components as those of the sound absorbing material 10 of the first embodiment are illustrated using common reference numerals, and the description thereof is omitted or simplified.

In the sound absorbing material 10A of the second embodiment, the surface material 22 laminated and adhered to the thermosetting resin-containing cured felt 31 is preferably a nonwoven fabric similar to the surface material 21 laminated and adhered to one surface of the polyurethane foam 11. . In particular, when the sound absorbing material 10A is used in an engine room, a polyester fiber nonwoven fabric excellent in heat resistance is preferable so that it can withstand high temperatures in the engine room. In particular, those made of needle-punched polyester fibers having a basis weight of 30 to 100 g / m ² are preferable. Furthermore, when one nonwoven fabric 21 is a nonwoven fabric facing the inside of the engine room and the other nonwoven fabric 22 is a nonwoven fabric facing the bonnet hood side, the nonwoven fabric 21 facing the inside of the engine room is the nonwoven fabric 22 facing the bonnet hood side. From the viewpoint of sound absorption, it is preferable to increase the basis weight of the polyester fiber. In particular, the nonwoven fabric 21 facing the inside of the engine compartment is preferably made of needle-punched polyester fibers having a basis weight of 100 g / m ² , and the nonwoven fabric 22 facing the bonnet hood side has a basis weight of 30 g / m ² . What consists of the polyester fiber which carried out the needle punch is preferable.

  The interface K1 between the polyurethane foam 11 and the surface material 21 and the interface K2 between the polyurethane foam 11 and the thermosetting resin-containing cured felt 31, and further between the thermosetting resin-containing cured felt 31 and the surface material 22. The interface K3 is bonded by curing the liquid binder as in the first embodiment.

  The manufacturing method related to the sound absorbing material 10A of the second embodiment is the same as the manufacturing method related to the sound absorbing material 10 of the first embodiment, and is a step of obtaining a catalyst-impregnated surface material of a liquid binder, a catalyst-free liquid binder-attached polyurethane foam. It consists of a process of obtaining, a laminating process, and a hot pressing process, and the following work is added in some processes.

  That is, in the step of obtaining the catalyst-impregnated surface material of the liquid binder, the catalyst-mixed emulsion E described in the first embodiment is applied and impregnated on both of the surface materials 21 and 22, and the catalyst-impregnated surface of the liquid binder Materials 21a and 22a are obtained. Moreover, in the said lamination process, as shown in FIG. 6, the said thermosetting resin containing uncured felt 31a is laminated | stacked on the single side | surface of the said catalyst-free liquid binder adhesion polyurethane foam 11a, and the said thermosetting resin containing uncured felt 31a. The catalyst-mixed emulsion-impregnated surface material 21a is laminated on the opposite surface to the catalyst-mixed emulsion on the thermosetting resin-free felt 31a, and the catalyst mixture is mixed on the surface opposite to the catalyst-free liquid binder-attached polyurethane foam 11a. The emulsion-impregnated surface material 22a is laminated to form a non-adhered four-layer laminate. In the hot press step, the unadhered four-layer laminate is hot pressed by hot press dies 41 and 42 as in the manufacturing method of the first embodiment. When hot pressing the liquid binder of the catalyst-free liquid binder-attached polyurethane foam 11a is in contact with the catalyst of the catalyst-mixed emulsion-impregnated surface material 21a, and the liquid binder is an isocyanate adhesive, the isocyanate adhesive is The catalyst mixed emulsion-impregnated surface material 21a also comes into contact with moisture. At that time, the isocyanate adhesive in contact with the moisture and the catalyst oozes out of the polyurethane foam by compression of the polyurethane foam by hot press, spreads over the entire laminate, and in this state is reacted and cured to bond the laminate together. . At the same time, the thermosetting resin of the thermosetting resin-containing uncured felt 31a is cured by heat at the time of hot pressing, and the laminate is shaped, and the sound absorbing material of the second embodiment shown in FIG. 10A is obtained. The sound absorbing material 10 </ b> A thus obtained has water repellency due to the water repellent contained in the surface material 11.

Hereinafter, specific examples will be described with respect to the sound absorbing material of the engine room adhered to the back side of the hood of the automobile. First, an aqueous emulsion of a water repellent in which a fluororesin is dispersed in water (trade name: Asahi Guard AG533S, manufactured by Asahi Glass Co., Ltd., solid content: 18%) and triethylenediamine as an amine catalyst for an isocyanate adhesive (Product name: DABCO 33LV, manufactured by Sankyo Air Products Co., Ltd.) 2.5 parts by weight were mixed to prepare a catalyst mixed emulsion. The isocyanate adhesive constituting the liquid binder containing no catalyst includes methylene diphenyl diisocyanate (trade name: 44V20, Sumitomo Bayer Urethane Co., Ltd.), and the non-woven fabric constituting the surface material 21 facing the inside of the engine room. Examples of the non-woven fabric constituting the surface material 22 facing the bonnet hood include 100 g / m ² needle punched polyester fiber, polyurethane foam 11 having a basis weight of 30 g / m ² needle punched polyester fiber. the soft slab polyurethane foam density 12 kg / ^{m 3} (part: RD10FR, manufactured by Inoac Corporation), as the thermosetting resin containing uncured felts 31a, a thermosetting resin containing uncured Fe containing phenolic resin Doo (basis weight of 500g / ^{m 2,} thickness 8mm, Howa made of a fiber-Industry Co., Ltd.) was used. The nonwoven fabric had a size of width 500 mm × length 500 mm regardless of the basis weight, and the polyurethane foam had a thickness of 20 mm × 500 mm × 500 mm. In addition, as a comparative example, miscellaneous wool products (thermosetting resin-free felt, basis weight 500 g / m ² , thickness 8 mm, manufactured by Toyoka Textile Industry Co., Ltd.), glass wool (trade name: Glassron wool, basis weight 1000 g / m ² , manufactured by Asahi Fiber Glass Co., Ltd.).

Regarding the sound absorbing material having the four-layer structure of Examples 1 and 2, the catalyst mixed emulsion is impregnated by spray coating with a spray gun on each side of the nonwoven fabric facing the engine room and the nonwoven fabric facing the hood hood side. In addition, regarding the sound absorbing material having the three-layer structure of Example 3, the catalyst mixed emulsion was spray-coated with a spray gun on one side of the nonwoven fabric facing the inside of the engine room. The coating amount is 100 g / m ² . Moreover, the said isocyanate adhesive agent which does not contain a catalyst was spray-coated with the spray gun on both surfaces of the said polyurethane foam, and it was made to impregnate. As shown in Table 1, the application amount of the isocyanate adhesive is 10 g / m ² in Example 1, 100 g / m ² in Example ² , and 50 g / m ² in Example 3.

  Next, as shown in FIG. 6, both surface materials (nonwoven fabrics) 21a and 22a impregnated with the catalyst mixed emulsion, polyurethane foam 11a coated with an isocyanate adhesive not containing catalyst, and thermosetting resin-containing uncured felt 31a is laminated and placed between the hot press dies 41 and 42, and is hot pressed at a hot press temperature of 195 ° C. for 60 seconds to a press thickness of 15 mm, and has a four-layer structure similar to the sound absorbing material 10A shown in FIG. The sound absorbing materials of Examples 1 and 2 were obtained. Further, as shown in FIG. 4, a surface material (nonwoven fabric) 21a impregnated with a catalyst mixed emulsion, a polyurethane foam 11a coated with an isocyanate adhesive not containing a catalyst, and a thermosetting resin-containing uncured felt 31a are laminated. An embodiment having a three-layer structure similar to that of the sound absorbing material 10 shown in FIG. 1, which is placed between the hot press dies 41 and 42 and hot pressed at a hot press temperature of 195 ° C. for 60 seconds and a press thickness of 15 mm. A sound absorbing material of 3 was obtained. The press surfaces of the hot press dies 41 and 42 are flat and have a size of 1000 mm × 1000 mm.

  Moreover, the sound-absorbing materials of Comparative Examples 1 to 4 shown in Table 1 were produced. Comparative Examples 1 and 2 are examples in which there is no thermosetting resin-containing cured felt, Comparative Example 3 is an example in which glass wool is used instead of urethane foam and thermosetting resin-containing cured felt, and Comparative Example 4 is a thermosetting resin. This is an example using a felt that does not include the inclusion.

  For the sound absorbing materials of Comparative Examples and Examples, a peel test, a water drop test, a skin exudation test, an overall basis weight, a sound absorption test, a bending test, and a thickness accuracy test were performed by the following methods. The measurement results are as shown in Table 1. In Comparative Example 3, the isocyanate adhesive soaked into the inside of the glass wool and was not used for bonding with the nonwoven fabric, and the skin peeled off after hot pressing, and each test such as a peel test could not be performed.

  In the peel test, a test piece having a width of 25 mm and a length of 150 mm is made on a nonwoven fabric and polyurethane foam facing the inside of the engine room, and the nonwoven fabric and polyurethane foam are peeled off over a length of 10 mm from one end of the test piece. A peel test was performed at a tensile rate of 200 mm / min by gripping the non-woven fabric and polyurethane foam. The evaluation was ○ when the polyurethane foam was destroyed, and × when the nonwoven fabric peeled at the interface.

  In the water drop test, one drop of water is dropped on the surface of the nonwoven fabric facing the inside of the engine room by a syringe, and then the state of the water drop is confirmed after 6 hours. In the case of the case (when it is no longer a hemisphere), it was set as x.

  In the skin exudation test, the surface of the non-woven fabric facing the inside of the engine room was visually observed, and the case where no exudation of the isocyanate adhesive was confirmed was evaluated as ◯, and the case where exudation was confirmed was evaluated as x.

  The total basis weight is a value obtained by dividing the weight of the sound absorbing material after heat pressing by the area of one side of each sound absorbing material, and was used for judging the light weight of the sound absorbing material.

  In the sound absorption test, the sound absorption was measured with a normal incidence sound absorption coefficient (JIS A 1405), and an average value was calculated for a sound absorption coefficient (unit%) of 1000 to 4000 Hz.

  In the bending test, two test pieces each having a size of 200 × 25 × thickness were supported, a load was applied to the central portion, the load at the yield point was read, and the load was used for evaluation of rigidity.

  In the thickness accuracy test, when the thickness after manufacture was 15 ± 1 mm with respect to the thickness of 15 mm set at the time of hot pressing, it was evaluated as ◯, and other than that as x.

  As shown in Table 1, the sound-absorbing materials of Examples 1 to 3 are all good results in the peel test, the water drop test, the skin exudation test, the bending test, and the thickness accuracy, and from the value of the overall basis weight. It was found that the weight of the sound-absorbing material of Comparative Example 3 (glass wool sound-absorbing material) was 1/2 to 1/3, and it was found to be lightweight. On the other hand, it has also confirmed that it has about 2 to 5 times the rigidity. Furthermore, the rigidity of Example 2 is increased by 1.5 times by increasing the application amount of the isocyanate adhesive of Example 1 from 10 g to 100 g. Moreover, the sound absorbing materials of Examples 1 to 3 are not inferior to the conventional (comparative example) sound absorbing materials in terms of sound absorption. From this, it can be seen that the sound absorbing materials of Examples 1 to 3 are lightweight and have high rigidity, and are suitable as a sound absorbing material for an engine room of an automobile that is required to be lightweight. The comparative example will be further described. Comparative example 1 has a significantly lower rigidity than that of the example, and comparative example 2 has a large amount of isocyanate adhesive applied, so that the isocyanate adhesive oozes out from the nonwoven fabric, and the release of the sound absorbing material from the mold. As a result, the adhesion between the glass wool and the non-woven fabric was poor as described above, and Comparative Example 3 did not become a good product. Moreover, the comparative example 4 was not able to perform shaping and shape fixation, the thickness precision was bad, and it did not become a favorable product.

It is sectional drawing of the sound-absorbing material which concerns on 1st embodiment of this invention. It is the schematic which shows the time of impregnating a catalyst mixed emulsion in a surface material at the time of manufacture of the sound-absorbing material which concerns on 1st embodiment. It is the schematic which shows at the time of apply | coating a liquid binder without a catalyst to both surfaces of a polyurethane foam at the time of manufacture of the sound-absorbing material which concerns on the first embodiment. It is sectional drawing which shows an example of the lamination | stacking at the time of manufacture of the sound-absorbing material which concerns on the first embodiment, and a hot press. It is sectional drawing of the sound-absorbing material which concerns on 2nd embodiment of this invention. It is sectional drawing which shows an example of lamination | stacking and the heat press at the time of manufacture of the sound-absorbing material which concerns on 2nd embodiment.

Explanation of symbols

10, 10A Sound absorbing material 11 Polyurethane foam 11a Polyurethane foam with catalyst-free liquid binder 21, 22 Surface material 21a, 22a Surface material with catalyst impregnated with liquid binder 31 Thermosetting resin-containing cured felt 31a Thermosetting resin-containing uncured felt K1 , K2, K3 interface 41, 42 Hot press mold

Claims (6)

  The polyurethane foam, a surface material laminated and adhered to one surface of the polyurethane foam, and a thermosetting resin-containing cured felt laminated and adhered to the surface of the polyurethane foam opposite to the surface material Sound absorbing material.   The sound absorbing material according to claim 1, wherein the sound absorbing material has a bending rigidity of 6 to 10 N / 25 mm.   The sound-absorbing material according to claim 1 or 2, wherein the surface material is laminated and bonded to one surface of the polyurethane foam and a surface of the thermosetting resin-containing cured felt opposite to the polyurethane foam. .   The sound absorbing material according to any one of claims 1 to 3, wherein the surface material is made of a nonwoven fabric. A step of impregnating the surface material with a catalyst mixed emulsion obtained by mixing a liquid binder catalyst with a water repellent aqueous emulsion to obtain a catalyst mixed emulsion impregnated surface material;
Applying a catalyst-free liquid binder on both sides of the polyurethane foam to obtain a catalyst-free liquid binder-attached polyurethane foam;
A thermosetting resin-containing uncured felt containing a thermosetting resin and at least a part of the thermosetting resin in an uncured state is laminated on one side of the catalyst-free liquid binder-attached polyurethane foam, Laminating the catalyst-mixed emulsion-impregnated surface material on the opposite side of the thermosetting resin-containing uncured felt in the contained liquid binder-attached polyurethane foam;
The laminated body of the thermosetting resin-containing uncured felt, the catalyst-free liquid binder-attached polyurethane foam, and the catalyst-mixed emulsion-impregnated surface material is hot-pressed to cure the liquid binder and integrate the laminated body. A hot press step of forming the thermosetting resin by curing the thermosetting resin of the thermosetting resin-containing uncured felt,
A method for producing a sound-absorbing material, comprising: The catalyst-free liquid binder in the thermosetting resin-containing uncured felt during the lamination step of the thermosetting resin-containing uncured felt, the catalyst-free liquid binder-attached polyurethane foam, and the catalyst mixed emulsion impregnated surface material The method for producing a sound-absorbing material according to claim 5, wherein the catalyst mixed emulsion-impregnated surface material is laminated on the surface opposite to the adhered polyurethane foam, followed by hot pressing.

Images